Halogenated terminal-containing self-assembled monomolecular layer hole transport material and synthesis method and application thereof
By designing self-assembled monolayer hole transport materials with halogenated ends, the interfacial contact properties of perovskite were improved, enhancing the interfacial charge transport performance of perovskite solar cells. This resulted in higher open-circuit voltage and improved photoelectric conversion efficiency, thus promoting the industrialization of perovskite solar cells.
Patent Information
- Application Number
- CN202411299149.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-18
- Publication Date
- 2026-03-20
AI Technical Summary
Existing perovskite solar cells use expensive and underperforming hole transport materials, which limits the improvement of cell efficiency and commercial applications. Improving interfacial charge transport performance is a key research focus.
We designed self-assembled monolayer hole transport materials with halogenated ends by introducing halogen and pseudohalogen groups at the ends of benzene rings to regulate the alkyl chain length, improve contact with the perovskite interface, and reduce energy loss.
It achieves higher open-circuit voltage and improved photoelectric conversion efficiency, and is suitable for single-junction and tandem perovskite solar cells, thus promoting industrialization.
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Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the technical field of perovskite solar cells, in particular to a self-assembled monolayer hole transport material containing a halogenated terminal and a synthesis method and application thereof. BACKGROUND
[0002] Photovoltaic technology is an important part of clean energy. As a typical representative of new photovoltaic technology, perovskite solar cells (PSCs) have rapidly become a research hotspot in the field of solar energy due to their high efficiency, low cost and printable characteristics. Since its advent in 2009, the photoelectric conversion efficiency (PCE) of PSCs has made astonishing progress in a short time, increasing from the initial 3.8% to 26.7% in more than ten years, which is comparable to traditional silicon solar cells.
[0003] Among the many PSCs structures, the inverted planar structure has the advantages of low temperature, high stability, full printing, and is easy to be used for series production of stacked devices with other solar cells such as silicon, copper indium gallium selenide and organic, and is the most promising structure to be commercialized first. However, the most commonly used hole transport material PTAA is expensive and has many performance deficiencies, which seriously limits the improvement of the efficiency of inverted PSCs and commercial application. Therefore, it is necessary to develop new hole transport materials to reduce the energy loss at the interface and improve the efficiency and stability of the cell.
[0004] The function of the hole transport material is to promote the effective transmission of photo-generated holes in the solar cell and block the reverse flow of electrons, thereby improving the photoelectric conversion efficiency of the device. The advantage of the self-assembled monolayer hole transport material (SAM-HTL) lies in its self-assembly property. A highly ordered and dense molecular layer can be formed on the surface of the substrate through chemical adsorption, which can effectively adjust the interface energy level matching and significantly reduce the interface defects and interface resistance. In addition, SAM-HTL has the designability of molecular structure, which allows the adjustment of the interface photoelectric properties by fine-tuning the end group, chain length and functional group of the molecule. Compared with traditional high molecular or small molecular hole transport materials, SAM-HTL has the advantages of thin layer structure, strong controllability, simple preparation, etc., which can significantly improve the stability and efficiency of photovoltaic devices, and has broad application prospects in inverted PSCs. However, how to further improve the interface charge transport performance is still the focus of current research.
[0005] The application is based on the previously developed diphenyl carbazole matrix, and the interface passivation performance and hole transport performance are regulated by different halogen substitution of the benzene ring end and regulation of the alkyl chain length. On the one hand, the introduction of different halogen groups can completely change the interface contact properties of the molecules and perovskite, thereby affecting the charge extraction and energy loss at the interface; on the other hand, the alkyl chains of different lengths have an important influence on charge transport and molecular packing. Therefore, the application designs a new self-assembled monolayer hole transport material based on the halogenated end substitution strategy, and applies it to a perovskite solar cell to improve the photovoltaic performance. SUMMARY
[0006] In order to solve the above technical problems, the application provides a self-assembled monolayer hole transport material containing a halogenated end and a synthesis method and application thereof, which is suitable for single-junction tandem PSCs, has strong interface passivation ability and good hole transport performance.
[0007] The application discloses a self-assembled monolayer hole transport material containing a halogenated end, which is Ph-nPACz-X, and the structural formula is as follows:
[0008]
[0009] wherein n is a positive integer of 2-10; and X is halogen or a pseudohalogen group.
[0010] The halogen can be iodine, bromine, chlorine and the like, and the pseudohalogen group can be a cyano group, a thiocyanato group and the like.
[0011] The material is based on diphenyl carbazole as a mother nucleus and alkyl phosphoric acid as an anchoring group, and the performance of the material is improved by regulating the end halogen substitution.
[0012] The application further discloses a synthesis method of the self-assembled monolayer hole transport material containing a halogenated end.
[0013]
[0014] Step one: coupling of carbazole borate and halogenated iodobenzene to obtain diphenyl carbazole substituted with an end halogen, namely Ph-Cz-X;
[0015] Step two: reaction of Ph-Cz-X with dibromoalkane to obtain Ph-Cz-X substituted with a bromoalkyl group, namely Ph-Cz-X-CnBr;
[0016] Step three: reaction of Ph-Cz-X-CnBr with triethyl phosphite to obtain Ph-Cz-X-CnBr substituted with diethyl phosphate, namely Ph-Cz-X-CnPOR;
[0017] Step four: hydrolysis of Ph-Cz-X-CnPOR water to obtain the final product Ph-nPACz-X.
[0018] wherein:
[0019] In step one, the reaction solvent is tetrahydrofuran, the catalyst used in the reaction is palladium tetra-triphenylphosphine, the base used in the reaction is sodium carbonate, and the reaction temperature is 60-150℃;
[0020] In step two, the strong base used in the reaction is potassium hydroxide, the phase transfer catalyst used in the reaction is tetrabutylammonium bromide, and the reaction temperature is 0-90℃;
[0021] In step three, the reaction is carried out under inert gas protection, the reaction solvent is triethyl phosphite, and the reaction temperature is 158-200℃;
[0022] In step four, the reaction is carried out under inert gas protection, the reaction solvent is tetrahydrofuran, the reaction temperature is 0-50℃, the hydrolysis reagent used in the reaction is trimethylsilyl bromide, and the quenching reagent used in the reaction is methanol.
[0023] The application further discloses an application of the self-assembled monolayer hole transport material with a halogenated terminal.
[0024] In the structure of the perovskite solar cell, the self-assembled monolayer hole transport material with a halogenated terminal is prepared into a hole transport layer by soaking, blade coating, spin coating, slot coating, LB film pulling or evaporation method.
[0025] In the structure of the perovskite solar cell, a perovskite layer is deposited onto the surface of the self-assembled monolayer hole transport material with a halogenated terminal by spin coating, blade coating, slot coating or evaporation method.
[0026] Further, the perovskite solar cell adopting the self-assembled monolayer hole transport material with a halogenated terminal to prepare a hole transport layer is used as a single-junction device or as one of sub-cells of a perovskite / perovskite tandem solar cell, a silicon / perovskite tandem solar cell, a copper indium gallium selenide / perovskite tandem solar cell or an organic / perovskite tandem solar cell.
[0027] Compared with the prior art, the application has the following beneficial effects:
[0028] The self-assembled monolayer hole transport material containing a halogenated end of the application takes carbazole with rigid conjugate plane as a mother nucleus, regulates the hole transport performance and molecular packing mode of the material by introducing benzene rings, introduces halogens such as iodine, bromine and chlorine and pseudo-halogen groups such as cyano and thiocyanogen at the end of the benzene ring to improve the contact and passivation with the perovskite interface and reduce the energy loss at the interface, and finally realizes the substrate self-assembly and effective hole transport by taking alkyl phosphoric acid with different lengths as an anchoring group. The synthesis method of the application is simple, the synthesis cost is low, and the prepared material can realize the dual functions of hole transport and perovskite interface passivation. When the material is applied to single-junction and stacked perovskite solar cells as a hole transport layer, the energy loss at the interface can be reduced, the open-circuit voltage and stability of the device can be improved, and the material has a wide application prospect. When the synthesized material is used as a hole transport layer, a high open-circuit voltage of >1.3V and a photoelectric conversion efficiency of >20% can be obtained, which perfectly meets the requirements of perovskite / perovskite, silicon / perovskite, copper indium gallium selenide / perovskite and organic / perovskite stacked solar cells, and is expected to help break through the theoretical efficiency limit of such batteries and promote the industrialization of perovskite solar cells.
[0029] The application starts from a diphenyl carbazole parent body, regulates the interface passivation performance and hole transport performance by different halogen substitution at the end of the benzene ring and regulating the length of the alkyl chain. On the one hand, the introduction of different halogen groups will completely change the interface contact properties of the molecule and the perovskite, thereby affecting the charge extraction and energy loss at the interface; on the other hand, the alkyl chain with different lengths has an important influence on charge transport and molecular packing. Therefore, the application designs a new type of self-assembled monolayer hole transport material based on halogenated end substitution strategy, and applies it to perovskite solar cells to improve the photovoltaic performance. BRIEF DESCRIPTION OF DRAWINGS
[0030] Figure 1 The nuclear magnetic hydrogen spectrum of Ph-Cz-Br prepared in the application;
[0031] Figure 2 The nuclear magnetic hydrogen spectrum of Ph-Cz-Br-C4Br prepared in the application;
[0032] Figure 3 The nuclear magnetic hydrogen spectrum of Ph-Cz-Br-C4POR prepared in the application;
[0033] Figure 4 The nuclear magnetic hydrogen spectrum of Ph-4PACz-Br prepared in the application;
[0034] Figure 5 The J-V curve of Ph-4PACz-Br prepared in the application as a hole transport material for single-junction perovskite solar cells;
[0035] Figure 6A single-junction perovskite solar cell structure prepared by the application. DETAILED DESCRIPTION
[0036] To further clarify the technical means and effects taken by the present application to achieve the predetermined inventive purpose, the specific embodiments, structures, features and effects thereof according to the present application are described in detail below in conjunction with the drawings and preferred embodiments.
[0037] Example 1
[0038] The application discloses a self-assembled monolayer hole transport material containing a halogenated terminal, which is Ph-4PACz-Br.
[0039] Synthesis of Ph-4PACz-Br
[0040]
[0041] Step one
[0042] 3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-carbazole (5.00 g, 11.93 mmol), 4-bromoiodobenzene (10.12 g, 35.79 mmol) and Pd(PPh3)4 (1.38 g, 1.19 mmol) were added into a round-bottom flask, tetrahydrofuran (200 mL, degassed by nitrogen) and Na2CO3 solution (60 mL, 2.0 M, degassed by nitrogen) were added, and the mixture was refluxed under the condition of nitrogen protection for 48 hours, after being cooled to room temperature, the mixed solution was extracted with CH2Cl2, washed with water, and the solvent was removed by rotary evaporation, and the crude product was separated by a chromatographic column, with petroleum ether / dichloromethane as the eluent (1:1, v / v), to obtain white solid Ph-Cz-Br, with a yield of about 80%.
[0043] The nuclear magnetic resonance hydrogen spectrum of Ph-Cz-Br prepared by the above method is shown in Figure 1 1 H NMR (400 MHz, CDCl3, δ): 8.31-8.25 (m, 2H), 8.17 (s, 1H), 7.63 (ddd, J = 8.4, 1.9, 1.0 Hz, 2H), 7.57 (d, J = 1.1 Hz, 8H), 7.49 (dt, J = 8.4, 0.8 Hz, 2H).
[0044] Step two
[0045] Into a 250 mL two-necked flask was added Ph-Cz-Br (1.00 g, 2.10 mmol), tetrabutylammonium bromide (0.10 g, 0.31 mmol), 1,4-dibromobutane (9.05 g, 41.91 mmol) and 50% aqueous KOH solution (1.18 g, 10.48 mmol) successively. The reaction mixture was heated to 65 °C and stirred for 24 h. After the reaction mixture was cooled to room temperature, it was washed with water and extracted with dichloromethane three times. The combined organic extracts were dried over anhydrous magnesium sulfate and filtered. The solvent was removed by rotary evaporation to give a crude product. The crude product was separated by column chromatography using petroleum ether / dichloromethane (4:1, v / v) as eluent to give Ph-Cz-Br-C4Br as a colorless oil in about 70% yield.
[0046] The H NMR spectrum of Ph-Cz-Br-C4Br prepared by the above method is shown in Figure 2 1 HNMR (400 MHz, CDC13, δ): 8.32 (s, 2H), 7.73-7.67 (m, 2H), 7.59 (d, J = 1.9 Hz, 8H), 7.48 (d, J = 8.5 Hz, 2H), 4.40 (d, J = 7.1 Hz, 2H), 3.42 (t, J = 6.4 Hz, 2H), 2.12 (s, 2H), 1.97 (d, J = 8.5 Hz, 2H).
[0047] Step Three:
[0048] Into a 100 mL two-necked flask was added Ph-Cz-Br-C4Br (1.00 g, 1.63 mmol) and triethyl phosphite (5.43 g, 32.67 mmol) successively. The reaction mixture was heated to reflux for 24 h. After the reaction mixture was cooled to room temperature, the solvent was removed by distillation under reduced pressure to give a crude product. The crude product was separated by column chromatography using petroleum ether / ethyl acetate (1:1, v / v) as eluent to give Ph-Cz-Br-C4POR as a colorless oil in about 90% yield.
[0049] The H NMR spectrum of Ph-Cz-Br-C4POR prepared by the above method is shown in Figure 3 1 H NMR (400 MHz, CDC13, δ): 8.33-8.26 (m, 2H), 7.67 (dt, J = 8.7, 2.2 Hz, 2H), 7.63-7.53 (m, 8H), 7.46 (dd, J = 8.5, 2.6 Hz, 2H), 4.35 (d, J = 7.8 Hz, 2H), 4.02 (ddt, J = 9.2, 5.2, 2.1 Hz, 4H), 2.02 (s, 2H), 1.79-1.65 (m, 4H), 1.23 (td, J = 7.1, 4.1 Hz, 6H).
[0050] Step four:
[0051] Into a 100 mL two-necked flask, Ph-Cz-Br-C4POR (1.00 g, 1.49 mmol) and 20 mL of anhydrous tetrahydrofuran were added under nitrogen protection, and then trimethylsilyl bromide (2.29 g, 14.94 mmol) was slowly added dropwise at room temperature. After stirring for 24 h, 10 mL of anhydrous methanol was added to quench the reaction, and then stirring was continued for 3 h. Finally, 300 mL of deionized water was added and stirring was continued for 24 h. The reaction solution was filtered and washed with water. The filter cake was redissolved in tetrahydrofuran, and then precipitated in petroleum ether and filtered. This process was repeated three times to obtain white solid Ph-4PACz-Br with a yield of about 75%.
[0052] The nuclear magnetic resonance hydrogen spectrum of Ph-4PACz-Br prepared by the above method is shown in Figure 4 1 HNMR (400 MHz, DMSO-d6, δ): δ 8.62 (s, 2H), 7.76 (t, J = 8.6 Hz, 6H), 7.70 (d, J = 8.6 Hz, 2H), 7.64 (d, J = 8.2 Hz, 4H), 4.43 (s, 2H), 1.87 (s, 2H), 1.52 (d, J = 9.8 Hz, 4H).
[0053] Example 2:
[0054] A perovskite solar cell was prepared by using the hole transport material Ph-4PACz-Br prepared in Example 1 as a hole transport layer, as shown in Figure 6 60 / BCP—Cu. The ITO glass was ultrasonically cleaned with alkaline glass cleaner, deionized water, acetone and isopropanol for 30 min. After drying under nitrogen, the ITO glass was plasma cleaned for 15 min. The Ph-4PACz-Br obtained in Example 1 was used as a hole transport layer, and the concentration of the ethanol solution was 0.5 mg mL -1 , spin-coated on the ITO glass surface and cleaned with ethanol to remove the excess Ph-4PACz-Br, and then annealed at 100℃ for 10min. Next, 1.5M Cs 0.2 FA 0.8 Pb(I 0.6 Br 0.4 )3 perovskite solution was spin-coated on the surface of Ph-4PACz-Br, and then annealed at 100℃ for 5min. After cooling, 20nm C 60 60 and 5nm BCP were respectively evaporated on the surface of perovskite film. Finally, a layer of 80nm Cu was vacuum evaporated as electrode, thus completing the preparation of perovskite solar cell device, and the effective area of the device was 4mm 2 . The open-circuit voltage, short-circuit current and fill factor of the prepared cell device were tested using a xenon lamp solar simulator with light source intensity of AM 1.5G, 100mW cm -2 .
[0055] Based on the Ph-4PACz-Br prepared in Example 1, perovskite solar cell devices were prepared and characterized according to the above procedure. The current-voltage (J-V) characteristic curve of the cell device performance is shown in Figure 5 , wherein the open-circuit voltage V oc is 1.31V, the short-circuit current density J sc is 18.86mA / cm 2 , the fill factor FF is 0.831, and the photoelectric conversion efficiency is 20.53%.
[0056] Therefore, the hole transport material involved in the present application can obtain a high open-circuit voltage of >1.3V and a photoelectric conversion efficiency of >20% without doping when applied to perovskite solar cells, which has a broad application prospect.
[0057] The above description is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes, without departing from the technical solution of the present application. Any simplification, modification, equivalent change and modification of the above embodiments made according to the technical essence of the present application, all still belong to the scope of the technical solution of the present application.
Claims
1. A self-assembled monolayer hole transport material with halogenated ends, characterized in that, Its structure is: Ph-nPACz-X; its structural formula is: Where n is a positive integer from 2 to 10; X is a halogen or pseudohalogen group.
2. A method for synthesizing a self-assembled monolayer hole transport material with halogenated ends as described in claim 1, characterized in that, The synthesis steps include the following: Step 1: Carbazole borate ester is coupled with haloiodobenzene to obtain terminal halogen-substituted diphenylcarbazole, namely Ph-Cz-X; Step 2: Ph-Cz-X reacts with dibromoalkane to give bromoalkane-substituted Ph-Cz-X, i.e., Ph-Cz-X-CnBr; Step 3: Ph-Cz-X-CnBr reacts with triethyl phosphite to obtain diethyl phosphate-substituted Ph-Cz-X-CnBr, i.e., Ph-Cz-X-CnPOR; Step 4: Hydrolyze Ph-Cz-X-CnPOR to obtain the final product Ph-nPACz-X.
3. The method for synthesizing a self-assembled monolayer hole transport material with halogenated ends as described in claim 2, characterized in that, In step one, the catalyst used in the reaction is tetrakis(triphenylphosphine)palladium, the base used in the reaction is sodium carbonate, and the reaction temperature is 60-150℃. In step two, the reaction solvent is tetrahydrofuran, the strong base used in the reaction is potassium hydroxide, the phase transfer catalyst used in the reaction is tetrabutylammonium bromide, and the reaction temperature is 0-90℃. In step three, the reaction is carried out under an inert gas atmosphere, the reaction solvent is triethyl phosphite, and the reaction temperature is 158-200℃. In step four, the reaction is carried out under an inert gas atmosphere, the reaction solvent is tetrahydrofuran, the reaction temperature is 0-50℃, the hydrolysis reagent used in the reaction is trimethylbromosilane, and the quenching reagent used in the reaction is methanol.
4. An application of the self-assembled monolayer hole transport material with halogenated ends as described in claim 1, characterized in that, Self-assembled monolayer hole transport materials with halogenated ends are applied to perovskite solar cells.
5. The application of the self-assembled monolayer hole transport material with halogenated ends as described in claim 4, characterized in that, In the structure of perovskite solar cells, hole transport layers are prepared by self-assembled monolayer hole transport materials with halogenated ends through methods such as immersion coating, blade coating, spin coating, slot coating, LB film stretching, or vapor deposition.
6. The application of the self-assembled monolayer hole transport material with halogenated ends as described in claim 4, characterized in that, In the structure of perovskite solar cells, the perovskite layer is deposited onto the surface of a self-assembled monolayer hole transport material with halogenated ends by spin coating, blade coating, slot coating or vapor deposition.
7. The application of a self-assembled monolayer hole transport material with halogenated ends as described in claim 5 or 6, characterized in that, The perovskite solar cell is used as a single-junction device or as one of the sub-cells of a perovskite / perovskite tandem solar cell, a silicon / perovskite tandem solar cell, a copper indium gallium selenide / perovskite tandem solar cell, or an organic / perovskite tandem solar cell.